| | Title | Creator | Description | Subject | Date |
|---|
| 76 |  | Dispersion effects in fiber optic interferometry | Christensen, Douglas A. | An extended analysis of the effects of uncompensated fiber dispersion on the fringe visibility of a fiber optic interferometer is developed, with particular emphasis on stellar interferometry. Both material and waveguide dispersion for single-mode, polarization-preserving fibers are considered. It... | Stellar interferometry; Fiber optics; Statistical optics | 1997 |
| 77 |  | Mechanical testing of metallic and polymeric intrafascicular electrodes | Horch, Kenneth W. | We are exploring alternatives to Pt/Ir wire for constructing ultra-flexible neural intrafascicular electrodes suitable for chronic implantation. In this study we measured the flexural properties of several kinds of fine metal wires and conducting polymer fibers. The fibers were made either of in... | Intrafascicular electrodes; Polymer fibers | 1994 |
| 78 |  | Using the cardiovascular system to illustrate fundamental laws and principles in a freshman course | Christensen, Douglas A. | Our Fundamentals of Bioengineering I course is organized around key physical and engineering laws and principles. A semester-long Major Project is assigned which integrates many of these principles by modeling the human systemic cardiovascular system, using both Matlab computer analysis and assembly... | Matlab | 2002 |
| 79 |  | Modeling sources in the FDTD formulation and their use in quantifying source and boundary condition errors | Christensen, Douglas A. | The modeling of voltage and current sources as either added or replaced sources in FDTD simulations is described and their differences discussed in terms of a transmission line analogy. An infinitesimal current element (ICE) is used to illustrate the validation of added source modeling and to study... | Finite-difference time-domain method; Infinitesimal current element | 1995-04 |
| 80 |  | Influence of temperature probe sheathing materials during ultrasonic heating | Christensen, Douglas A. | The influence of sheathing materials upon temperature probes used during the monitoring of ultrasonic heating was measured. The measurements show that the sheathing can be heated in a manner not representative of the temperature rise occurring in the surrounding material, altering the probe reading... | Ultrasonic hyperthermia; Sheathing; Phantom tests; Teflon | 1986-05 |
| 81 |  | Information contrained in sensory nerve recordings made with intrafascicular electrodes | Horch, Kenneth W. | Multiunit recordings were made in anesthetized cats with chronically implanted intrafascicular electrodes over a period of six months. Neural signals recorded with these electrodes consisted of activity in sensory fibers innervating a variety of cutaneous mechanoreceptors. Mechanical stimuli wer... | Intrafascicular electrodes; Functional electrical stimulation (FES); Closed-loop control | 1991 |
| 82 |  | Interface of forest and agriculture in nonpoint pollution control | Christensen, Douglas A. | Management practices of agriculture, including conservation and tillage options, recently have received a great deal of attention with respect to their impact upon the environment. Research efforts have focused both on the direct impacts of reduced on-site productivity resulting from the erosion of ... | Suspended sediment; Channel erosion; Silviculture | 1983 |
| 83 |  | Multiple sensor optical thermometry system for application in clinical hyperthermia | Christensen, Douglas A. | The thermometry system described is based upon the temperature dependence of the band edge absorption of infrared light in GaAs crystal. The design of the thermometry was completed, and the system was subjected to an extensive evaluation, including testing with tissue phantoms and microwave applic... | Thermometry; Hyperthermia applicator; Phantom tests | 1984-01 |
| 84 |  | Muscle recruitment through electrical stimulation of the lumbo-sacral spinal cord | Horch, Kenneth W. | The goal of this study was to determine the feasibility of producing graded muscle contraction in individual muscles or muscle groups by electrically stimulating motor neurons in the lumbo-sacral spinal cord. Recruitment curves were obtained for quadriceps, tibialis anterior and triceps surae/pl... | Functional neuromuscular stimulation (FNS); Motor pools, Muscle recruitment, Spinal cord stimulation | 2000 |
| 85 |  | Muscle recruitment with intrafascicular electrodes | Horch, Kenneth W. | We have studied muscle recruitment with Tefloninsulated, 25 pm diameter, Pt-Ir intrafasicular electrodes implanted in nerves innervating the gastrocnemius and soleus muscles of cats. The purpose of this study was to measure the performance of these bipolar electrodes, which had been designed to... | Functional neuromuscular stimulation (FNS); Intrafascicular electrode | 1991 |
| 86 |  | Resonant inductive applicator for neck hyperthermia | Christensen, Douglas A. | We have designed and phantom tested an inductive applicator especially suited for producing hyperthermia in cancerous regions in the neck. The applicator is tuned to resonate near 27 MHz; its inductive nature has the advantage of efficient coupling to the irregular neck anatomy. An inhomogeneou... | Hyperthermia applicator; Phantom tests | 1989 |
| 87 |  | Are the extrinsic muscles better suited for signaling joint angles or finger tip location? | Horch, Kenneth W. | We used a biomechanical model of the human long finger to determine whether the extrinsic muscles are better suited for estimating the finger's joint angles or for estimating location of the finger tip. We found that two of the extrinsic muscles together could provide information sufficient to direc... | Extrinsic muscles; Metacarpophalangeal joint; Biomechanical models | 1997 |
| 88 |  | Control of ankle position using neural feedback | Horch, Kenneth W. | This paper describes a closed loop control system that uses afferent neural activity from muscle spindle fibers as feedback for controlling ankle position. The gastrocnemius muscle was stimulated through a dual channel intrafascicular electrode implanted in a fascicle of the tibial nerve. Dual cha... | Neuromuscular stimulation; Peripheral nerve; Joint angle | 1994 |
| 89 |  | Characterization of a four-camera ratiometric optical mapping system | Collins, Zachary J.; Poelzing, Steven | Electrical activity precedes calcium mediated heart contractions. Optical mapping takes advantage of minimally invasive fluorescent molecular probes to image both electrical and calcium activity. These molecular probes allow for ratiometric imaging. We characterize a four camera system capable of... | Optical mapping; Ratiometric imaging; Di-4-ANEPPS; Indo-1; Trapeze Interactive Poster | 2010-03-15 |
| 90 |  | Characterizing growth patterns in longitudinal MRI using image contrast | Vardhan, Avantika | Understanding the growth patterns of the early brain is crucial to the study of neuro-development. In the early stages of brain growth, a rapid sequence of biophysical and chemical processes take place. A crucial component of these processes, known as myelination, consists of the formation of a myel... | | 2014-01-01 |
| 91 |  | Circuits for local and global signal integration in primary visual cortex | Angelucci, Alessandra; Lund, Jennifer S. | Contrast-dependent changes in spatial summation and contextual modulation of primary visual cortex (V1) neuron responses to stimulation of their receptive field reveal long-distance integration of visual signals within V1, well beyond the classical receptive field (cRF) of single neurons. To identif... | Primary Visual Cortex; Extrastriate Cortex; Feed-back Connections; Lateral Connections; SUrround Modulation; Macaque | 2002-10-01 |
| 92 |  | Classification of action potentials in multi unit intrafascicular recordings using neural network pattern recognition techniques | Horch, Kenneth W. | Neural network pattern-recognition techniques were applied to the problem of identifying the sources of action potentials in multi-unit neural recordings made from intrafascicular electrodes implanted in cats. The network was a three-layer connectionist machine that used digitized action potenti... | Intrafascicular electrodes; Multi-unit neural activity; Artificial neural networks | 1994 |
| 93 |  | Closed loop control of ankle position using muscle afferent feedback with functional neuromuscular stimulation | Horch, Kenneth W. | This paper describes a closed-loop functional neuromuscular stimulation system that uses afferent neural activity from muscle spindle fibers as feedback for controlling position of the ankle joint. Ankle extension against a load was effected by neural stimulation through a dual channel intrafasc... | Neuromuscular stimulation; Functional neuromuscular stimulation (FNS); Neural electrodes | 1996 |
| 94 |  | Selective activation of functional muscle groups through stimulation of spinal motor pools | Horch, Kenneth W. | A microelectrode was used to stimulate motor neurons in the lumbo-sacral spinal cord of adult cats. Consistent with spinal cord anatomical studies, we found that the motor neurons responsible for activation of individual muscle groups are situated together in specific areas of the cord, forming mot... | Spinal motor pools | 1993 |
| 95 |  | Selective activation of muscle groups in the feline hindlimb thorough electrical microstimulation of the ventral lumbo-sacral spinal cord | Horch, Kenneth W. | Selective activation of muscle groups in the feline hindlimb by electrical stimulation of the ventral lumbo-sacral spinal cord was investigated. Spinal cord segments L5 to S1 were mapped using a penetrating tungsten needle electrode. Locations that produced isolated contraction of quadriceps, ti... | Functional electrical stimulation; Motor pools; Spinal chord stimulation | 2000 |
| 96 |  | Laser diode coherence length variation with drive current: a tool for dispersion measurements | Christensen, Douglas A. | A visible light (670nm) laser diode was used as a variable coherence length source to measure dispersion characteristics in single-mode fibers. The diode's spectral width, measured against increasing drive current, was found to change from about 16 nanometers to less than 0.2 nanometer. The corresp... | Laser diode; Fiber interferometry | 1992 |
| 97 |  | Extending the two-dimensional FDTD method to hybrid electromagnetic systems with active and passive lumped elements | Christensen, Douglas A. | This paper extends the finite-difference time-domain (FDTD) method to include distributed electromagnetic systems with lumped elements (a hybrid system) and voltage and current sources. FDTD equations that include nonlinear elements like diodes and transistors are derived. Calculation of driving-p... | Finite-difference time-domain method; Lumped elements | 1992-04 |
| 98 |  | FDTD modeling in the design of optical chemical sensor structures | Christensen, Douglas A. | The finite-difference time-domain method (FDTD) is a numerical technique for solving Maxwell's equations in a discretized space and time frame. It has been used extensively in the analysis of electrically large structures in the microwave domain, but has only recently been applied to optical proble... | Finite-difference time-domain method; Immunochemical fluorosensors; Planar waveguides | 1991 |
| 99 |  | Microfabricated cylindrical multielectrodes for neural stimulation | Horch, Kenneth W. | The effects of spinal cord injuries are likely to be ameliorated with the help of functional electrical stimulation of the spinal cord, a technique that may benefit from a new style of electrode: the cylindrical multielectrode. This paper describes the specifications for, fabrication techniques for... | Cylindrical multielectrode; Depth electrodes; Impedance testing; Microelectromechanical systems (MEMS); Microstimulation; Impedance testing; Neural prosthesis | 2006-02 |
| 100 |  | Mitigating spinal cord injury | Jenson, Justin Michael; Bock, Susan C. | How would your life change if you became one of the 15,000 Americans to suffer a spinal cord injury this year? Trauma to the spinal cord causes immediate loss of function below the level of the injury. Then, in the hours and days after the accident, the body's secondary injury response may extend ... | Trapeze Interactive Poster | 2010-03-15 |
